Hormone and thinking-performance links in defence personnel rest on limited evidence
A review of defence and security personnel linked hormone concentrations outside normal ranges with poorer cognitive performance, but widespread study weaknesses prevent firm conclusions about those relationships.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Among defence and security personnel, hormone concentrations outside levels described as normal generally appeared linked with poorer performance on thinking tasks. Most included studies were rated low to moderate in quality, however. The review therefore leaves the hormone-performance relationship uncertain and does not establish that changing a hormone level would improve task performance.
Common problems included participants dropping out and missing blinding, randomization or advance sample-size calculations. Research groups were based in North America and Western Europe, and the included personnel were predominantly male.
The evidence was uneven
Cortisol and testosterone received the most attention. Oestrogen, oxytocin, growth hormone and melatonin were studied less often in these personnel. The review therefore cannot support equally developed conclusions for every hormone or every type of operational role.
Task performance needs its own evidence
The review examined controlled hormone interventions and assessed relationships with cognitive performance, meaning performance on thinking tasks. Its broad summary does not provide a reliable numerical effect or show that a hormone association explains operational success.
The original publication
A systematic review of hormonal changes, their effects on, and associations with, cognitive performance within defence and security personnel.
O'Malley CA, Vine SJ, Arthur T et al.
Physiol Behav · 2025
- PubMed ID
- 40618863
- Record checked
AI-assisted research and writing. This explains one selected publication; it is not a complete review of everything known. Our approach.
One more question, understood.
Keep track of the research you’ve explored.